diff --git a/src/compiler/transformers/core-runtime-apis.ts b/src/compiler/transformers/core-runtime-apis.ts
index 5ba0ec6f4ba..faab64d5247 100644
--- a/src/compiler/transformers/core-runtime-apis.ts
+++ b/src/compiler/transformers/core-runtime-apis.ts
@@ -1,6 +1,5 @@
 import type * as d from '../../declarations';
 
-export const ATTACH_SHADOW = '__stencil_attachShadow';
 export const CREATE_EVENT = '__stencil_createEvent';
 export const DEFINE_CUSTOM_ELEMENT = '__stencil_defineCustomElement';
 export const GET_ELEMENT = '__stencil_getElement';
@@ -12,7 +11,6 @@ export const REGISTER_HOST = '__stencil_registerHost';
 export const H = '__stencil_h';
 
 export const RUNTIME_APIS = {
-  attachShadow: `attachShadow as ${ATTACH_SHADOW}`,
   createEvent: `createEvent as ${CREATE_EVENT}`,
   defineCustomElement: `defineCustomElement as ${DEFINE_CUSTOM_ELEMENT}`,
   getElement: `getElement as ${GET_ELEMENT}`,
diff --git a/src/compiler/transformers/test/core-runtime-apis.spec.ts b/src/compiler/transformers/test/core-runtime-apis.spec.ts
index 1a46582ba09..eb098fee806 100644
--- a/src/compiler/transformers/test/core-runtime-apis.spec.ts
+++ b/src/compiler/transformers/test/core-runtime-apis.spec.ts
@@ -21,23 +21,23 @@ describe('addCoreRuntimeApi()', () => {
     expect(mockModule.coreRuntimeApis).toBeDefined();
     expect(mockModule.coreRuntimeApis).toHaveLength(0);
 
-    addCoreRuntimeApi(mockModule, RUNTIME_APIS.attachShadow);
-    expect(mockModule.coreRuntimeApis).toEqual([RUNTIME_APIS.attachShadow]);
+    addCoreRuntimeApi(mockModule, RUNTIME_APIS.Host);
+    expect(mockModule.coreRuntimeApis).toEqual([RUNTIME_APIS.Host]);
 
     addCoreRuntimeApi(mockModule, RUNTIME_APIS.createEvent);
-    expect(mockModule.coreRuntimeApis).toEqual([RUNTIME_APIS.attachShadow, RUNTIME_APIS.createEvent]);
+    expect(mockModule.coreRuntimeApis).toEqual([RUNTIME_APIS.Host, RUNTIME_APIS.createEvent]);
   });
 
   it("does not allow duplicate entries in a module's coreRuntimeApis", () => {
     expect(mockModule.coreRuntimeApis).toBeDefined();
     expect(mockModule.coreRuntimeApis).toHaveLength(0);
 
-    addCoreRuntimeApi(mockModule, RUNTIME_APIS.attachShadow);
-    expect(mockModule.coreRuntimeApis).toEqual([RUNTIME_APIS.attachShadow]);
+    addCoreRuntimeApi(mockModule, RUNTIME_APIS.Host);
+    expect(mockModule.coreRuntimeApis).toEqual([RUNTIME_APIS.Host]);
 
     // attempt to add the api again, doing so shall not create a duplicate entry
-    addCoreRuntimeApi(mockModule, RUNTIME_APIS.attachShadow);
-    expect(mockModule.coreRuntimeApis).toEqual([RUNTIME_APIS.attachShadow]);
+    addCoreRuntimeApi(mockModule, RUNTIME_APIS.Host);
+    expect(mockModule.coreRuntimeApis).toEqual([RUNTIME_APIS.Host]);
   });
 });
 
@@ -57,12 +57,12 @@ describe('addOutputTargetCoreRuntimeApi()', () => {
     expect(mockModule.outputTargetCoreRuntimeApis).toBeDefined();
     expect(Object.entries(mockModule.outputTargetCoreRuntimeApis)).toHaveLength(0);
 
-    addOutputTargetCoreRuntimeApi(mockModule, DIST_CUSTOM_ELEMENTS, RUNTIME_APIS.attachShadow);
-    expect(mockModule.outputTargetCoreRuntimeApis).toEqual({ [DIST_CUSTOM_ELEMENTS]: [RUNTIME_APIS.attachShadow] });
+    addOutputTargetCoreRuntimeApi(mockModule, DIST_CUSTOM_ELEMENTS, RUNTIME_APIS.Host);
+    expect(mockModule.outputTargetCoreRuntimeApis).toEqual({ [DIST_CUSTOM_ELEMENTS]: [RUNTIME_APIS.Host] });
 
     addOutputTargetCoreRuntimeApi(mockModule, DIST_CUSTOM_ELEMENTS, RUNTIME_APIS.createEvent);
     expect(mockModule.outputTargetCoreRuntimeApis).toEqual({
-      [DIST_CUSTOM_ELEMENTS]: [RUNTIME_APIS.attachShadow, RUNTIME_APIS.createEvent],
+      [DIST_CUSTOM_ELEMENTS]: [RUNTIME_APIS.Host, RUNTIME_APIS.createEvent],
     });
   });
 
@@ -70,12 +70,12 @@ describe('addOutputTargetCoreRuntimeApi()', () => {
     expect(mockModule.outputTargetCoreRuntimeApis).toBeDefined();
     expect(Object.entries(mockModule.outputTargetCoreRuntimeApis)).toHaveLength(0);
 
-    addOutputTargetCoreRuntimeApi(mockModule, DIST_CUSTOM_ELEMENTS, RUNTIME_APIS.attachShadow);
-    expect(mockModule.outputTargetCoreRuntimeApis).toEqual({ [DIST_CUSTOM_ELEMENTS]: [RUNTIME_APIS.attachShadow] });
+    addOutputTargetCoreRuntimeApi(mockModule, DIST_CUSTOM_ELEMENTS, RUNTIME_APIS.Host);
+    expect(mockModule.outputTargetCoreRuntimeApis).toEqual({ [DIST_CUSTOM_ELEMENTS]: [RUNTIME_APIS.Host] });
 
     // attempt to add the api again, doing so shall not create a duplicate entry
-    addOutputTargetCoreRuntimeApi(mockModule, DIST_CUSTOM_ELEMENTS, RUNTIME_APIS.attachShadow);
-    expect(mockModule.outputTargetCoreRuntimeApis).toEqual({ [DIST_CUSTOM_ELEMENTS]: [RUNTIME_APIS.attachShadow] });
+    addOutputTargetCoreRuntimeApi(mockModule, DIST_CUSTOM_ELEMENTS, RUNTIME_APIS.Host);
+    expect(mockModule.outputTargetCoreRuntimeApis).toEqual({ [DIST_CUSTOM_ELEMENTS]: [RUNTIME_APIS.Host] });
   });
 });